Micromechanical Dispersive Element for High-Speed Spectral Analysis
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Solution Overview
Problem
Existing devices for determining spectral properties of surfaces are limited by inflexibility, high component costs, and slow detection speeds, particularly in the infrared range, due to mechanical complexity and the need for multiple detectors and filters.
Innovation Solution
A compact device with a micromechanical dispersive element that can be deflected about two axes, allowing for simultaneous spectral and spatial resolution, using a single point detector and controlled by a unit that adjusts the dispersive element's movement for quick wavelength changes and flexible operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If filter wheels are used for wavelength selection, then spectral information can be recorded simultaneously with detector arrays, but the device becomes slow and inflexible when setting different wavelength ranges
Solution Approach 1:
The patent replaces mechanical filter wheels with an acousto-optical tunable filter (AOTF) that uses acoustic waves to diffract and select wavelengths. This substitution eliminates the mechanical rotation and switching mechanisms of filter wheels, achieving faster wavelength changes without mechanical inertia or wear, while maintaining the capability to scan across spectral ranges.
Solution Approach 2:
The AOTF enables dynamic wavelength selection by changing the frequency and amplitude of acoustic waves in real-time. This allows continuous tuning across wavelength ranges without mechanical movement, providing flexible and rapid spectral scanning capabilities that adapt to different detection requirements.
2Adaptability or versatility
If acousto-optical or electro-optical filters are used for wavelength selection, then wavelength ranges can be adjusted, but the adjustable wavelength range is very limited and the device becomes strongly temperature-dependent
Solution Approach 1:
The patent changes the operating parameters of the AOTF, specifically operating it at cryogenic temperatures (e.g., liquid nitrogen temperature of 77K or lower). This parameter change extends the usable wavelength range into the mid-infrared region and stabilizes the acoustic wave propagation against temperature variations, reducing the temperature dependence that plagues room-temperature acousto-optical devices.
Solution Approach 2:
The system utilizes the phase transition to cryogenic temperatures to fundamentally change the material properties of the AOTF. At these low temperatures, the acoustic velocity and refractive index become highly stable, enabling precise wavelength selection across a broad spectral range without the thermal drift problems of room-temperature operation.
3Productivity
If detector arrays are used to record spectral properties, then spectral information can be captured simultaneously, but the device becomes very expensive especially for the near infrared range
Solution Approach 1:
The patent extracts only the necessary spectral information point-by-point using a single detector instead of requiring a full detector array. The AOTF sequentially presents different wavelengths to the single detector, allowing spectral scanning without the expense of multiple detectors. This approach maintains spectral detection capability while eliminating the high cost of infrared detector arrays.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables high-speed, cost-effective, and flexible spectral analysis with reduced component costs, suitable for both visible and infrared ranges, by using a micromechanical dispersive element that oscillates or deflects to achieve rapid wavelength selection and spatial scanning.
Implementation Method 1
at least one dispersive element (2) for the spectral decomposition of light (3)
Implementation Method 2
the dispersive element is formed from a micromechanical component, preferably consisting of silicon. Ideally, this is a micromechanical mirror with an applied grid
Data Source
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AI summary
The invention relates to a device (1) for determining, in particular linear or area-wise, the spectral properties of a surface, comprising at least one movable dispersive element (2) for the spectral decomposition of light (3). According to the invention, the at least one dispersive element (2) is arranged to be deflectable about two axes (4, 5). The invention further relates to a use of a device (1) according to the invention. Furthermore, the invention relates to a method for determining, in particular linear or area-wise, the spectral properties of a surface, wherein at least one dispersive element (2) for the spectral decomposition of light (3) is arranged to be movable.